BS 7835 Copper AWA/SWA LSZH Cable

What is BS 7835 Copper AWA/SWA LSZH 3.8/6.6kV Cable?

The BS 7835 Copper AWA/SWA LSZH 3.8/6.6kV Cable is an armoured, copper conductor medium-voltage power distribution cable manufactured in strict compliance with British Standard BS 7835 and international standard IEC/EN 60228. Operating at a rated system voltage of 3.8/6.6 (7.2)kV with an AC test voltage rating of 15kV, it provides primary electrical power transmission across public utility grids, transformer substations, mass transit networks, and enclosed commercial infrastructure where enhanced fire safety, reduced smoke emission, and zero toxic acid gas release are required under fire conditions.

The construction utilizes Class 2 stranded compacted circular copper conductors insulated with dry-cured XLPE and screened with extruded semi-conductive layers and concentric copper wires with copper tape beneath an extruded LSZH bedding layer. Mechanical armoring is matched to core geometry: single-core cables use non-magnetic Aluminium Wire Armour (AWA) to prevent magnetic hysteresis losses and overheating, while three-core cables utilize Galvanised Steel Wire Armour (SWA) to provide mechanical impact and crush protection for direct subterranean burial. Finished with an extruded red LSZH outer jacket, the cable is UV resistant, flame retardant per IEC/EN 60332-1-2 and IEC/EN 60332-3-24, and certified for low smoke density (IEC/EN 61034-1/2) and zero halogens (IEC/EN 60754-1/2) across open-air runs, cable duct banks, and direct burial trenches.

BS 7835 Copper AWA/SWA LSZH 3.8/6.6kV Cable Construction

• Conductor: Class 2 stranded compacted copper conductor conforming to IEC/EN 60228.
• Conductor Screen: Extruded semi-conductive Cross-Linked Polyethylene (XLPE) compound to maintain radial electrostatic field uniformity.
• Insulation: High-grade Cross-Linked Polyethylene (XLPE) compound providing dielectric strength up to +90°C continuous operating temperature.
• Insulation Screen: Extruded semi-conductive Cross-Linked Polyethylene (XLPE) layer bonded to the dielectric insulation.
• Metallic Screen: Concentric copper wires and equalizing copper tape to conduct single-phase short-circuit fault currents.
• Separator: Binding tape applied over the screened cores.
• Inner Sheath (Bedding): Extruded Low Smoke Zero Halogen (LSZH) compound serving as an inner protective cushion under the armour.
• Armour: Single-core cables feature non-magnetic Aluminium Wire Armour (AWA); multi-core cables feature Galvanised Steel Wire Armour (SWA).
• Outer Sheath: UV-resistant, flame-retardant Low Smoke Zero Halogen (LSZH) compound.
• Sheath Colour: Red.

Applications

BS 7835 copper armoured LSZH cables are engineered for primary medium-voltage power distribution across demanding industrial, utility, and public infrastructure installations:

• Direct Burial in Ground: Subsurface trench installation directly in soil without additional conduit protection, utilizing the impact resistance of SWA or AWA wire armour.
• Underground Cable Ducting: Pulled through subterranean concrete duct banks, utility raceways, and road crossings where high pulling tension and crush resistance are required.
• External Power Networks: Primary 6.6kV distribution circuits linking regional utility substations, switching stations, and step-down transformers.
• Enclosed & Populated Public Infrastructure: Underground rail transit systems, airport terminals, highway tunnels, and commercial complexes requiring LSZH smoke emission compliance.
• Industrial Facilities & Data Centers: Power delivery lines for manufacturing facilities and mission-critical server facilities requiring protection against corrosive acid gas release during fire.

Specifications & Dimensions

Huadong Cable Group manufactures BS 7835 Copper AWA/SWA LSZH 3.8/6.6 (7.2)kV cables across single-core configurations from 35mm² up to 630mm² (35, 50, 70, 95, 120, 150, 185, 240, 300, 400, 500, and 630mm²) and three-core assemblies from 50mm² up to 400mm² (50, 70, 95, 120, 150, 185, 240, 300, and 400mm²) in strict compliance with BS 7835. Rated for 3.8/6.6 (7.2)kV with an AC factory test voltage of 15kV, single-core AWA cables feature overall nominal diameters from 24.30mm to 55.80mm and unit weights from 1,023 kg/km to 8,212 kg/km, while three-core SWA cables feature overall outer diameters from 48mm to 89mm and nominal weights spanning 4,500 kg/km to 19,000 kg/km. Operating within a fixed temperature envelope of -15°C to +90°C (maximum conductor short-circuit withstand of +250°C for 5 seconds and an initial screen short-circuit limit of +80°C), maximum copper conductor DC resistance at 20°C ranges from 0.524 Ω/km (35mm²) down to 0.0283 Ω/km (630mm²). Continuous current ratings reach up to 1,180A in air (flat) and 981A in ground (flat) for 630mm² single-core cables, and up to 726A in air and 653A in ground for 400mm² three-core cables. Standard minimum installation bending radii are 15 × overall diameter for single-core (12 × OD adjacent to joints/terminations when controlled using a former) and 12 × overall diameter for multi-core (10 × OD adjacent to joints/terminations when controlled using a former) in strict accordance with BS 7835 and IEC/EN 60228 standards.

Standards

Design & Material Standards: BS 7835, IEC/EN 60228 Class 2
Low Smoke Zero Halogen Performance: Low Smoke Halogen Free according to IEC/EN 60754-1/2, IEC/EN 61034-1/2
Flame Retardancy & Environmental: Flame Retardant according to IEC/EN 60332-1-2, IEC/EN 60332-3-24; UV Resistant
Voltage & Electrical Ratings: Voltage Rating Uo/U (Um): 3.8/6.6 (7.2)kV; AC Test Voltage: 15kV
Thermal Ratings: Fixed Operating Temperature: -15°C to +90°C; Conductor Short-Circuit Limit (5s): +250°C; Initial Metallic Screen Short-Circuit Temp: +80°C
Bending Performance: Single core: 15 × OD (12 × OD controlled at joints); Multi core: 12 × OD (10 × OD controlled at joints)
Regulatory Compliance: RoHS Directive 2015/65/EU, REACH Regulation EC 1907/2006, CE Marked

Frequently Asked Questions

Q: What is the primary difference between BS 7835 and BS 6622 3.8/6.6kV copper cables?
A: BS 6622 cables utilize PVC bedding and outer sheaths, whereas BS 7835 cables incorporate Low Smoke Zero Halogen (LSZH) bedding and outer jackets, ensuring essential life-safety compliance by restricting toxic gases, corrosive acid fumes, and dense smoke during fire incidents.

Q: Why is Aluminium Wire Armour (AWA) specified for single-core cables instead of Steel Wire Armour (SWA)?
A: Single-core AC cables use non-magnetic aluminium wire armour (AWA) to eliminate electromagnetic induction that would otherwise produce circulating eddy currents and excessive heat build-up in magnetic steel wire armour.

Q: What mechanical protection does Galvanised Steel Wire Armour (SWA) provide for three-core cables?
A: SWA incorporates a circular layer of heavy galvanized steel wires that provides high longitudinal tensile strength during pulling and shields the core assembly against crushing loads, ground subsidence, and sharp stone penetration during direct underground burial.

Q: What standard delivery lead time does Huadong Cable offer for international project orders?
A: Our standard manufacturing lead time ranges from 15 to 25 working days depending on order quantity, cable specification, and custom reel lengths, backed by expedited factory scheduling for critical project requirements.

BS 7835 Copper AWA/SWA LSZH 3.8/6.6kV Cable – Why Choose Huadong Cable?

Huadong Cable Group manufactures BS 7835 Copper AWA/SWA LSZH 3.8/6.6 (7.2)kV medium-voltage cables in strict compliance with British Standard BS 7835 and IEC/EN 60228 specifications. Utilizing high-purity electrolytic copper rod, our precision stranding machinery produces Class 2 stranded compacted circular conductors that ensure tight dimensional tolerance, optimal compaction density, and minimum electrical DC resistance. On our triple-extrusion catenary continuous vulcanization (CCV) lines, the semi-conductive conductor screen, high-cleanliness XLPE insulation, and semi-conductive insulation screen are applied simultaneously under pressurized dry nitrogen vulcanization, eliminating microscopic voids and keeping partial discharge levels well below standard limits.

Backed by more than 20 years of precision cable engineering expertise, Huadong Cable Group operates testing laboratories accredited under ISO/IEC 17025 and quality management systems certified to ISO 9001 and CE frameworks. Direct factory manufacturing eliminates middleman trading markups, allowing us to provide competitive factory pricing, 100% routine electrical and spark testing verified by certified Mill Test Certificates (MTC), continuous drum cuts packaged on heavy-duty ISPM 15 heat-treated export wooden reels, and dependable logistics for international electric utilities, infrastructure developers, and industrial EPC contractors worldwide.